I'm a graduate student working on a project that involves well points, each associated with a measure of nitrate. I also have HUC10 watershed delineations, which I plan to use to breakdown the data later. I ran ordinary kriging through the Geostatistical Analyst using the nitrate well points and choose the Gaussian model. I ran into two problems here:

1) The kriging output did not automatically format itself as a raster dataset. Instead, I had to convert it, but by doing so it distorted the surface. Is this normal? I tried kriging via the toolbox, and it seemed to have converted it just fine. Does this mean I can't use the Geostatistical Analyst?

2) When I ran zonal statistics on the interpolated raster surface, using the HUC10 as the zone layer, the ArcToolBox would crash. This happens on multiple computers at different locations. Is there a way to get around this?

Basically, I'm trying to do a hotspot/coldspot analysis of the nitrates by HUC10 zones. But there are over 600 HUC10 zones.

The main idea is that a geostatistical layer is really a mathematical model that takes an (x,y) location and returns a value (as opposed to a raster that has values stored in each cell). A geostatistical layer doesn't "know" its own values until you ask it to calculate them. The contours that you see in a geostatistical layer are made from a quick contouring algorithm: the model makes the fewest calculations that it can in order to draw roughly accurate contours.

When you export a geostatistical layer to a raster, all it is doing is calling the mathematical function at the center of every raster cell. This obviously requires many more calculations than drawing quick contours, so the surfaces may appear a bit different (sometimes very different).

I am PhD student and I have the same problem. If you solve the problem, may you share the solution with me? Thank you very much. Firdes.

Hello,

I'm a graduate student working on a project that involves well points, each associated with a measure of nitrate. I also have HUC10 watershed delineations, which I plan to use to breakdown the data later. I ran ordinary kriging through the Geostatistical Analyst using the nitrate well points and choose the Gaussian model. I ran into two problems here:

1) The kriging output did not automatically format itself as a raster dataset. Instead, I had to convert it, but by doing so it distorted the surface. Is this normal? I tried kriging via the toolbox, and it seemed to have converted it just fine. Does this mean I can't use the Geostatistical Analyst?

2) When I ran zonal statistics on the interpolated raster surface, using the HUC10 as the zone layer, the ArcToolBox would crash. This happens on multiple computers at different locations. Is there a way to get around this?

Basically, I'm trying to do a hotspot/coldspot analysis of the nitrates by HUC10 zones. But there are over 600 HUC10 zones.

I created a bathymetry map of a lake using the geostatistical analyst (i.e. creating a GA layer). I re-classified the depths for my purpose and would now like to export the GA layer to a raster file (GA layer to Grid). When exporting I want the output cell size to be 1.The interesting thing is that I did all this successfully in arcmap 9.3, yet in arcmap 10.0 it doesn't work.

So, I can run the GA (Kriging/CoKriging; default parameters worked best for my purpose) without any problems and do get a nice GA layer. This is what happens when I try to export the GA layer to a raster file:

2) When I choose to change the output cell size to 1 (which is in fact what I want), then a raster file is in fact produced. However, the high and low values are completely off (high: 3,40282e+038; highest value should be something around 4,2). When I try to classify (Properties, Symbology), I get the following error message: Failed to initialize classify renderer (possibly too many unique values).

- I guess you are in a geographic coordinate system (i.e degrees decimal), not a good idea as 1 degree longtitude <> 1 degree latitude.- default size cell produces an output raster of roughly 250 columns and 250 rows- with you changing the cell size to 1 will mean that your output raster will have roughly 1 row and 1 column- I notice that you are in a comma locale and using ArcGIS10, have you installed the latest Service Pack (SP5)?- 3.4e38 is a NoData value, which basically means that your output raster is empty.

Thanks for the tip with the coordinate system: I converted my shapefiles from WGS 1984 to RT90 (swedish grid), which made the whole process work just fine:- GA layer (Kriging/CoKriging)- GA layer to Grid (raster, changing output cell size to 1; I need it to be one so that I can calculate the volumes at the various depths)